The invention relates to a method of preparing an unsaturated fatty acid dry concentrate as well as a composition comprising at least one unsaturated fatty acid and food, beverages and drugs comprising said composition.
Fatty acids (alcanic acids) are structural elements of lipids, phosphoglycerides, glycolipids, cholestrol esterases and waxes. They consist of an extended, usually unbranched hydrocarbon chain and a terminal carboxyl group. The chain either is saturated or contains one or several nonconjugated cis double bindings; the latter being denoted as unsaturated fatty acids. Higher animals lack the cytochrome-b5-ADPH-dependent oxygenase system required to form unsaturated fatty acids, wherefor linolic and linolenic acids belong to their essential fatty acids, i.e., their demand for such fatty acids must be met via food intake.
While, until some years ago, linolic acid (omega-6 fatty acid; C 18:2 (9,12)) was regarded as the sole value-determining factor for the supply of unsaturated fatty acids in dietary food, recent scientific findings have focused on the biological and essential importance of other unsaturated fatty acids such as, for instance, linolenic acid, stearidonic acid, oleic acid, erucic acid, nervic acid, palmitoleic acid and vaccenic acid. These (highly) unsaturated fatty acids are considered to be of a high biological and nutrition-medical relevance, in particular, in respect to prostaglandin (i.e., inflammatory) metabolism, heart and circulation, carbohydrate metabolism (diabetes), overweight, skin metabolism (neurodermitis, psoriasis), hormone metabolism, performances of the central nervous system, lungs (asthma), joints (arthritis), immune system (allergies, cancer, AIDS), autoimmune diseases, degenerative diseases of the joints, growth processes of infants and adolescents, athletes' and heavy workers' metabolisms, and aging processes. The adequate and well-balanced supply of (highly) unsaturated fatty acids is, therefore, necessary to optimize health.
Unsaturated fatty acids occur in different concentrations, primarily in unrefined vegetable oils, all of which have an oily character. Some of these oils, in particular hempseed oil, linseed oil and fish oil, in addition, have a strong, penetrating inherent smell and taste, which largely limits the wide use of such oils despite their high health values.
Another problem involved in food enriched with unsaturated fatty acids consists in that the unrefined and hence unsaturated-fatty-acid-rich oils have only a very limited storage quality and their applicability is largely reduced on account of their oily consistency. In order to avoid the above-mentioned drawbacks and produce products enriched with unsaturated fatty acids, which will also be accepted by consumers, such oils are processed in a technologically complex procedure. Due to the strict production conditions required for such processing, unsaturated fatty acids are, however, altered to such an extent that their high health values get lost. Moreover, the processing of the cited oils to common drug forms such as capsules, tablets or liquids, in turn, only insufficiently satisfies the daily demands required from a nutrition-physiological point of view, which are in the gram range, due to the dose volumes limited on account of the drug forms mentioned.
WO 87/03899 describes a method of preparing an omega-3 concentrate by esterifying the fatty acid fraction of fish oil at room temperature. After this, the alkyl ester is precipitated and separated upon heating to 55 to 90° C. and subsequent cooling to 0° C. Subsequent purification by extraction with a solvent yields the desired product. This method, however, comprises several steps in which the unsaturated fatty acids are subjected to relatively severe conditions (large temperature fluctuations, different solvents and buffers, etc.) so that a portion of the unsaturated fatty acids will be modified or lost.
U.S. Pat. No. 6,030,645 is concerned with dry particles comprising an oleophilic active substance dispersed in a carrier material, which particles are coated with a composition containing calcium silicate. The oleophilic substance is, for instance, arachidonic acid, carotenoids or the like. Cellulose, maltodextrin, alginate, lactate, gum, gelatin, sugar, sugar alcohol and starch are, inter alia, cited as carrier material examples. These particles are produced by mixing the oleophilic substance with the carrier material and spraying this mixture into calcium silicate such that the oleophilic particles formed by spraying will be coated with calcium silicate. The particles are then dried.
According to JP 6181725 A, a composition comprising a readily oxidizable oily substance is introduced into a porous carrier by pressure reduction in a manner that the composition displaces the air in this porous carrier.
FR 2 758 055 A1 relates to a powdery substance comprising oil based on unsaturated fatty acids and an absorbent, such as starch. The oil and the absorbent are homogenized and atomized in order to obtain microparticles, whereupon the water contained in those microparticles is evaporated.
U.S. Pat. No. 5,106,639 A describes a process for preparing fodder additives by mixing, and subsequently drying to powdery form, a carrier, an emulsifier and an oil containing omega-3 fatty acids. The carrier may be, for instance, soybean protein, starch, pectin, gelatin, collagen, casein and the like.
EP 0 424 578 A1 refers to a dry mixture comprising an oil containing unsaturated fatty acids and caseinate, whereby these two substances are mixed together, whereupon the composition is dried.
DE 4 411 414 C1 describes a product for enterally feeding fatty acids and/or amino acids as well as a method of preparing such a product by incorporating said fatty acids into the amylose helix by extrusion along with starch so as to form inclusion complexes. After this, the mass may be dried.
U.S. Pat. No. 4,559,222 A discloses a composition comprising a drug, which composition further includes a mineral oil and silicon dioxide.
All of the methods described above involve, however, the drawback that high-quality oils having high portions of unsaturated fatty acids are treated without sufficient care so that too high a portion of unsaturated fatty acids will be lost in the course of the method.